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1/* linux/net/ipv4/arp.c
2 *
3 * Copyright (C) 1994 by Florian La Roche
4 *
5 * This module implements the Address Resolution Protocol ARP (RFC 826),
6 * which is used to convert IP addresses (or in the future maybe other
7 * high-level addresses) into a low-level hardware address (like an Ethernet
8 * address).
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Fixes:
16 * Alan Cox : Removed the Ethernet assumptions in
17 * Florian's code
18 * Alan Cox : Fixed some small errors in the ARP
19 * logic
20 * Alan Cox : Allow >4K in /proc
21 * Alan Cox : Make ARP add its own protocol entry
22 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
23 * Stephen Henson : Add AX25 support to arp_get_info()
24 * Alan Cox : Drop data when a device is downed.
25 * Alan Cox : Use init_timer().
26 * Alan Cox : Double lock fixes.
27 * Martin Seine : Move the arphdr structure
28 * to if_arp.h for compatibility.
29 * with BSD based programs.
30 * Andrew Tridgell : Added ARP netmask code and
31 * re-arranged proxy handling.
32 * Alan Cox : Changed to use notifiers.
33 * Niibe Yutaka : Reply for this device or proxies only.
34 * Alan Cox : Don't proxy across hardware types!
35 * Jonathan Naylor : Added support for NET/ROM.
36 * Mike Shaver : RFC1122 checks.
37 * Jonathan Naylor : Only lookup the hardware address for
38 * the correct hardware type.
39 * Germano Caronni : Assorted subtle races.
40 * Craig Schlenter : Don't modify permanent entry
41 * during arp_rcv.
42 * Russ Nelson : Tidied up a few bits.
43 * Alexey Kuznetsov: Major changes to caching and behaviour,
44 * eg intelligent arp probing and
45 * generation
46 * of host down events.
47 * Alan Cox : Missing unlock in device events.
48 * Eckes : ARP ioctl control errors.
49 * Alexey Kuznetsov: Arp free fix.
50 * Manuel Rodriguez: Gratuitous ARP.
51 * Jonathan Layes : Added arpd support through kerneld
52 * message queue (960314)
53 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
54 * Mike McLagan : Routing by source
55 * Stuart Cheshire : Metricom and grat arp fixes
56 * *** FOR 2.1 clean this up ***
57 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
58 * Alan Cox : Took the AP1000 nasty FDDI hack and
59 * folded into the mainstream FDDI code.
60 * Ack spit, Linus how did you allow that
61 * one in...
62 * Jes Sorensen : Make FDDI work again in 2.1.x and
63 * clean up the APFDDI & gen. FDDI bits.
64 * Alexey Kuznetsov: new arp state machine;
65 * now it is in net/core/neighbour.c.
66 * Krzysztof Halasa: Added Frame Relay ARP support.
67 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
68 * Shmulik Hen: Split arp_send to arp_create and
69 * arp_xmit so intermediate drivers like
70 * bonding can change the skb before
71 * sending (e.g. insert 8021q tag).
72 * Harald Welte : convert to make use of jenkins hash
73 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
74 */
75
76#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
77
78#include <linux/module.h>
79#include <linux/types.h>
80#include <linux/string.h>
81#include <linux/kernel.h>
82#include <linux/capability.h>
83#include <linux/socket.h>
84#include <linux/sockios.h>
85#include <linux/errno.h>
86#include <linux/in.h>
87#include <linux/mm.h>
88#include <linux/inet.h>
89#include <linux/inetdevice.h>
90#include <linux/netdevice.h>
91#include <linux/etherdevice.h>
92#include <linux/fddidevice.h>
93#include <linux/if_arp.h>
94#include <linux/skbuff.h>
95#include <linux/proc_fs.h>
96#include <linux/seq_file.h>
97#include <linux/stat.h>
98#include <linux/init.h>
99#include <linux/net.h>
100#include <linux/rcupdate.h>
101#include <linux/slab.h>
102#ifdef CONFIG_SYSCTL
103#include <linux/sysctl.h>
104#endif
105
106#include <net/net_namespace.h>
107#include <net/ip.h>
108#include <net/icmp.h>
109#include <net/route.h>
110#include <net/protocol.h>
111#include <net/tcp.h>
112#include <net/sock.h>
113#include <net/arp.h>
114#include <net/ax25.h>
115#include <net/netrom.h>
116
117#include <linux/uaccess.h>
118
119#include <linux/netfilter_arp.h>
120
121/*
122 * Interface to generic neighbour cache.
123 */
124static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
125static int arp_constructor(struct neighbour *neigh);
126static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
127static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
128static void parp_redo(struct sk_buff *skb);
129
130static const struct neigh_ops arp_generic_ops = {
131 .family = AF_INET,
132 .solicit = arp_solicit,
133 .error_report = arp_error_report,
134 .output = neigh_resolve_output,
135 .connected_output = neigh_connected_output,
136};
137
138static const struct neigh_ops arp_hh_ops = {
139 .family = AF_INET,
140 .solicit = arp_solicit,
141 .error_report = arp_error_report,
142 .output = neigh_resolve_output,
143 .connected_output = neigh_resolve_output,
144};
145
146static const struct neigh_ops arp_direct_ops = {
147 .family = AF_INET,
148 .output = neigh_direct_output,
149 .connected_output = neigh_direct_output,
150};
151
152static const struct neigh_ops arp_broken_ops = {
153 .family = AF_INET,
154 .solicit = arp_solicit,
155 .error_report = arp_error_report,
156 .output = neigh_compat_output,
157 .connected_output = neigh_compat_output,
158};
159
160struct neigh_table arp_tbl = {
161 .family = AF_INET,
162 .key_len = 4,
163 .hash = arp_hash,
164 .constructor = arp_constructor,
165 .proxy_redo = parp_redo,
166 .id = "arp_cache",
167 .parms = {
168 .tbl = &arp_tbl,
169 .reachable_time = 30 * HZ,
170 .data = {
171 [NEIGH_VAR_MCAST_PROBES] = 3,
172 [NEIGH_VAR_UCAST_PROBES] = 3,
173 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
174 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
175 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
176 [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
177 [NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024,
178 [NEIGH_VAR_PROXY_QLEN] = 64,
179 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
180 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
181 [NEIGH_VAR_LOCKTIME] = 1 * HZ,
182 },
183 },
184 .gc_interval = 30 * HZ,
185 .gc_thresh1 = 128,
186 .gc_thresh2 = 512,
187 .gc_thresh3 = 1024,
188};
189EXPORT_SYMBOL(arp_tbl);
190
191int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
192{
193 switch (dev->type) {
194 case ARPHRD_ETHER:
195 case ARPHRD_FDDI:
196 case ARPHRD_IEEE802:
197 ip_eth_mc_map(addr, haddr);
198 return 0;
199 case ARPHRD_INFINIBAND:
200 ip_ib_mc_map(addr, dev->broadcast, haddr);
201 return 0;
202 case ARPHRD_IPGRE:
203 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
204 return 0;
205 default:
206 if (dir) {
207 memcpy(haddr, dev->broadcast, dev->addr_len);
208 return 0;
209 }
210 }
211 return -EINVAL;
212}
213
214
215static u32 arp_hash(const void *pkey,
216 const struct net_device *dev,
217 __u32 *hash_rnd)
218{
219 return arp_hashfn(*(u32 *)pkey, dev, *hash_rnd);
220}
221
222static int arp_constructor(struct neighbour *neigh)
223{
224 __be32 addr = *(__be32 *)neigh->primary_key;
225 struct net_device *dev = neigh->dev;
226 struct in_device *in_dev;
227 struct neigh_parms *parms;
228
229 rcu_read_lock();
230 in_dev = __in_dev_get_rcu(dev);
231 if (in_dev == NULL) {
232 rcu_read_unlock();
233 return -EINVAL;
234 }
235
236 neigh->type = inet_addr_type(dev_net(dev), addr);
237
238 parms = in_dev->arp_parms;
239 __neigh_parms_put(neigh->parms);
240 neigh->parms = neigh_parms_clone(parms);
241 rcu_read_unlock();
242
243 if (!dev->header_ops) {
244 neigh->nud_state = NUD_NOARP;
245 neigh->ops = &arp_direct_ops;
246 neigh->output = neigh_direct_output;
247 } else {
248 /* Good devices (checked by reading texts, but only Ethernet is
249 tested)
250
251 ARPHRD_ETHER: (ethernet, apfddi)
252 ARPHRD_FDDI: (fddi)
253 ARPHRD_IEEE802: (tr)
254 ARPHRD_METRICOM: (strip)
255 ARPHRD_ARCNET:
256 etc. etc. etc.
257
258 ARPHRD_IPDDP will also work, if author repairs it.
259 I did not it, because this driver does not work even
260 in old paradigm.
261 */
262
263#if 1
264 /* So... these "amateur" devices are hopeless.
265 The only thing, that I can say now:
266 It is very sad that we need to keep ugly obsolete
267 code to make them happy.
268
269 They should be moved to more reasonable state, now
270 they use rebuild_header INSTEAD OF hard_start_xmit!!!
271 Besides that, they are sort of out of date
272 (a lot of redundant clones/copies, useless in 2.1),
273 I wonder why people believe that they work.
274 */
275 switch (dev->type) {
276 default:
277 break;
278 case ARPHRD_ROSE:
279#if IS_ENABLED(CONFIG_AX25)
280 case ARPHRD_AX25:
281#if IS_ENABLED(CONFIG_NETROM)
282 case ARPHRD_NETROM:
283#endif
284 neigh->ops = &arp_broken_ops;
285 neigh->output = neigh->ops->output;
286 return 0;
287#else
288 break;
289#endif
290 }
291#endif
292 if (neigh->type == RTN_MULTICAST) {
293 neigh->nud_state = NUD_NOARP;
294 arp_mc_map(addr, neigh->ha, dev, 1);
295 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
296 neigh->nud_state = NUD_NOARP;
297 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
298 } else if (neigh->type == RTN_BROADCAST ||
299 (dev->flags & IFF_POINTOPOINT)) {
300 neigh->nud_state = NUD_NOARP;
301 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
302 }
303
304 if (dev->header_ops->cache)
305 neigh->ops = &arp_hh_ops;
306 else
307 neigh->ops = &arp_generic_ops;
308
309 if (neigh->nud_state & NUD_VALID)
310 neigh->output = neigh->ops->connected_output;
311 else
312 neigh->output = neigh->ops->output;
313 }
314 return 0;
315}
316
317static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
318{
319 dst_link_failure(skb);
320 kfree_skb(skb);
321}
322
323static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
324{
325 __be32 saddr = 0;
326 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
327 struct net_device *dev = neigh->dev;
328 __be32 target = *(__be32 *)neigh->primary_key;
329 int probes = atomic_read(&neigh->probes);
330 struct in_device *in_dev;
331
332 rcu_read_lock();
333 in_dev = __in_dev_get_rcu(dev);
334 if (!in_dev) {
335 rcu_read_unlock();
336 return;
337 }
338 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
339 default:
340 case 0: /* By default announce any local IP */
341 if (skb && inet_addr_type(dev_net(dev),
342 ip_hdr(skb)->saddr) == RTN_LOCAL)
343 saddr = ip_hdr(skb)->saddr;
344 break;
345 case 1: /* Restrict announcements of saddr in same subnet */
346 if (!skb)
347 break;
348 saddr = ip_hdr(skb)->saddr;
349 if (inet_addr_type(dev_net(dev), saddr) == RTN_LOCAL) {
350 /* saddr should be known to target */
351 if (inet_addr_onlink(in_dev, target, saddr))
352 break;
353 }
354 saddr = 0;
355 break;
356 case 2: /* Avoid secondary IPs, get a primary/preferred one */
357 break;
358 }
359 rcu_read_unlock();
360
361 if (!saddr)
362 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
363
364 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
365 if (probes < 0) {
366 if (!(neigh->nud_state & NUD_VALID))
367 pr_debug("trying to ucast probe in NUD_INVALID\n");
368 neigh_ha_snapshot(dst_ha, neigh, dev);
369 dst_hw = dst_ha;
370 } else {
371 probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
372 if (probes < 0) {
373 neigh_app_ns(neigh);
374 return;
375 }
376 }
377
378 arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
379 dst_hw, dev->dev_addr, NULL);
380}
381
382static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
383{
384 struct net *net = dev_net(in_dev->dev);
385 int scope;
386
387 switch (IN_DEV_ARP_IGNORE(in_dev)) {
388 case 0: /* Reply, the tip is already validated */
389 return 0;
390 case 1: /* Reply only if tip is configured on the incoming interface */
391 sip = 0;
392 scope = RT_SCOPE_HOST;
393 break;
394 case 2: /*
395 * Reply only if tip is configured on the incoming interface
396 * and is in same subnet as sip
397 */
398 scope = RT_SCOPE_HOST;
399 break;
400 case 3: /* Do not reply for scope host addresses */
401 sip = 0;
402 scope = RT_SCOPE_LINK;
403 in_dev = NULL;
404 break;
405 case 4: /* Reserved */
406 case 5:
407 case 6:
408 case 7:
409 return 0;
410 case 8: /* Do not reply */
411 return 1;
412 default:
413 return 0;
414 }
415 return !inet_confirm_addr(net, in_dev, sip, tip, scope);
416}
417
418static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
419{
420 struct rtable *rt;
421 int flag = 0;
422 /*unsigned long now; */
423 struct net *net = dev_net(dev);
424
425 rt = ip_route_output(net, sip, tip, 0, 0);
426 if (IS_ERR(rt))
427 return 1;
428 if (rt->dst.dev != dev) {
429 NET_INC_STATS_BH(net, LINUX_MIB_ARPFILTER);
430 flag = 1;
431 }
432 ip_rt_put(rt);
433 return flag;
434}
435
436/* OBSOLETE FUNCTIONS */
437
438/*
439 * Find an arp mapping in the cache. If not found, post a request.
440 *
441 * It is very UGLY routine: it DOES NOT use skb->dst->neighbour,
442 * even if it exists. It is supposed that skb->dev was mangled
443 * by a virtual device (eql, shaper). Nobody but broken devices
444 * is allowed to use this function, it is scheduled to be removed. --ANK
445 */
446
447static int arp_set_predefined(int addr_hint, unsigned char *haddr,
448 __be32 paddr, struct net_device *dev)
449{
450 switch (addr_hint) {
451 case RTN_LOCAL:
452 pr_debug("arp called for own IP address\n");
453 memcpy(haddr, dev->dev_addr, dev->addr_len);
454 return 1;
455 case RTN_MULTICAST:
456 arp_mc_map(paddr, haddr, dev, 1);
457 return 1;
458 case RTN_BROADCAST:
459 memcpy(haddr, dev->broadcast, dev->addr_len);
460 return 1;
461 }
462 return 0;
463}
464
465
466int arp_find(unsigned char *haddr, struct sk_buff *skb)
467{
468 struct net_device *dev = skb->dev;
469 __be32 paddr;
470 struct neighbour *n;
471
472 if (!skb_dst(skb)) {
473 pr_debug("arp_find is called with dst==NULL\n");
474 kfree_skb(skb);
475 return 1;
476 }
477
478 paddr = rt_nexthop(skb_rtable(skb), ip_hdr(skb)->daddr);
479 if (arp_set_predefined(inet_addr_type(dev_net(dev), paddr), haddr,
480 paddr, dev))
481 return 0;
482
483 n = __neigh_lookup(&arp_tbl, &paddr, dev, 1);
484
485 if (n) {
486 n->used = jiffies;
487 if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) {
488 neigh_ha_snapshot(haddr, n, dev);
489 neigh_release(n);
490 return 0;
491 }
492 neigh_release(n);
493 } else
494 kfree_skb(skb);
495 return 1;
496}
497EXPORT_SYMBOL(arp_find);
498
499/* END OF OBSOLETE FUNCTIONS */
500
501/*
502 * Check if we can use proxy ARP for this path
503 */
504static inline int arp_fwd_proxy(struct in_device *in_dev,
505 struct net_device *dev, struct rtable *rt)
506{
507 struct in_device *out_dev;
508 int imi, omi = -1;
509
510 if (rt->dst.dev == dev)
511 return 0;
512
513 if (!IN_DEV_PROXY_ARP(in_dev))
514 return 0;
515 imi = IN_DEV_MEDIUM_ID(in_dev);
516 if (imi == 0)
517 return 1;
518 if (imi == -1)
519 return 0;
520
521 /* place to check for proxy_arp for routes */
522
523 out_dev = __in_dev_get_rcu(rt->dst.dev);
524 if (out_dev)
525 omi = IN_DEV_MEDIUM_ID(out_dev);
526
527 return omi != imi && omi != -1;
528}
529
530/*
531 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
532 *
533 * RFC3069 supports proxy arp replies back to the same interface. This
534 * is done to support (ethernet) switch features, like RFC 3069, where
535 * the individual ports are not allowed to communicate with each
536 * other, BUT they are allowed to talk to the upstream router. As
537 * described in RFC 3069, it is possible to allow these hosts to
538 * communicate through the upstream router, by proxy_arp'ing.
539 *
540 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
541 *
542 * This technology is known by different names:
543 * In RFC 3069 it is called VLAN Aggregation.
544 * Cisco and Allied Telesyn call it Private VLAN.
545 * Hewlett-Packard call it Source-Port filtering or port-isolation.
546 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
547 *
548 */
549static inline int arp_fwd_pvlan(struct in_device *in_dev,
550 struct net_device *dev, struct rtable *rt,
551 __be32 sip, __be32 tip)
552{
553 /* Private VLAN is only concerned about the same ethernet segment */
554 if (rt->dst.dev != dev)
555 return 0;
556
557 /* Don't reply on self probes (often done by windowz boxes)*/
558 if (sip == tip)
559 return 0;
560
561 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
562 return 1;
563 else
564 return 0;
565}
566
567/*
568 * Interface to link layer: send routine and receive handler.
569 */
570
571/*
572 * Create an arp packet. If (dest_hw == NULL), we create a broadcast
573 * message.
574 */
575struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
576 struct net_device *dev, __be32 src_ip,
577 const unsigned char *dest_hw,
578 const unsigned char *src_hw,
579 const unsigned char *target_hw)
580{
581 struct sk_buff *skb;
582 struct arphdr *arp;
583 unsigned char *arp_ptr;
584 int hlen = LL_RESERVED_SPACE(dev);
585 int tlen = dev->needed_tailroom;
586
587 /*
588 * Allocate a buffer
589 */
590
591 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
592 if (skb == NULL)
593 return NULL;
594
595 skb_reserve(skb, hlen);
596 skb_reset_network_header(skb);
597 arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
598 skb->dev = dev;
599 skb->protocol = htons(ETH_P_ARP);
600 if (src_hw == NULL)
601 src_hw = dev->dev_addr;
602 if (dest_hw == NULL)
603 dest_hw = dev->broadcast;
604
605 /*
606 * Fill the device header for the ARP frame
607 */
608 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
609 goto out;
610
611 /*
612 * Fill out the arp protocol part.
613 *
614 * The arp hardware type should match the device type, except for FDDI,
615 * which (according to RFC 1390) should always equal 1 (Ethernet).
616 */
617 /*
618 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
619 * DIX code for the protocol. Make these device structure fields.
620 */
621 switch (dev->type) {
622 default:
623 arp->ar_hrd = htons(dev->type);
624 arp->ar_pro = htons(ETH_P_IP);
625 break;
626
627#if IS_ENABLED(CONFIG_AX25)
628 case ARPHRD_AX25:
629 arp->ar_hrd = htons(ARPHRD_AX25);
630 arp->ar_pro = htons(AX25_P_IP);
631 break;
632
633#if IS_ENABLED(CONFIG_NETROM)
634 case ARPHRD_NETROM:
635 arp->ar_hrd = htons(ARPHRD_NETROM);
636 arp->ar_pro = htons(AX25_P_IP);
637 break;
638#endif
639#endif
640
641#if IS_ENABLED(CONFIG_FDDI)
642 case ARPHRD_FDDI:
643 arp->ar_hrd = htons(ARPHRD_ETHER);
644 arp->ar_pro = htons(ETH_P_IP);
645 break;
646#endif
647 }
648
649 arp->ar_hln = dev->addr_len;
650 arp->ar_pln = 4;
651 arp->ar_op = htons(type);
652
653 arp_ptr = (unsigned char *)(arp + 1);
654
655 memcpy(arp_ptr, src_hw, dev->addr_len);
656 arp_ptr += dev->addr_len;
657 memcpy(arp_ptr, &src_ip, 4);
658 arp_ptr += 4;
659
660 switch (dev->type) {
661#if IS_ENABLED(CONFIG_FIREWIRE_NET)
662 case ARPHRD_IEEE1394:
663 break;
664#endif
665 default:
666 if (target_hw != NULL)
667 memcpy(arp_ptr, target_hw, dev->addr_len);
668 else
669 memset(arp_ptr, 0, dev->addr_len);
670 arp_ptr += dev->addr_len;
671 }
672 memcpy(arp_ptr, &dest_ip, 4);
673
674 return skb;
675
676out:
677 kfree_skb(skb);
678 return NULL;
679}
680EXPORT_SYMBOL(arp_create);
681
682/*
683 * Send an arp packet.
684 */
685void arp_xmit(struct sk_buff *skb)
686{
687 /* Send it off, maybe filter it using firewalling first. */
688 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
689}
690EXPORT_SYMBOL(arp_xmit);
691
692/*
693 * Create and send an arp packet.
694 */
695void arp_send(int type, int ptype, __be32 dest_ip,
696 struct net_device *dev, __be32 src_ip,
697 const unsigned char *dest_hw, const unsigned char *src_hw,
698 const unsigned char *target_hw)
699{
700 struct sk_buff *skb;
701
702 /*
703 * No arp on this interface.
704 */
705
706 if (dev->flags&IFF_NOARP)
707 return;
708
709 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
710 dest_hw, src_hw, target_hw);
711 if (skb == NULL)
712 return;
713
714 arp_xmit(skb);
715}
716EXPORT_SYMBOL(arp_send);
717
718/*
719 * Process an arp request.
720 */
721
722static int arp_process(struct sk_buff *skb)
723{
724 struct net_device *dev = skb->dev;
725 struct in_device *in_dev = __in_dev_get_rcu(dev);
726 struct arphdr *arp;
727 unsigned char *arp_ptr;
728 struct rtable *rt;
729 unsigned char *sha;
730 __be32 sip, tip;
731 u16 dev_type = dev->type;
732 int addr_type;
733 struct neighbour *n;
734 struct net *net = dev_net(dev);
735 bool is_garp = false;
736
737 /* arp_rcv below verifies the ARP header and verifies the device
738 * is ARP'able.
739 */
740
741 if (in_dev == NULL)
742 goto out;
743
744 arp = arp_hdr(skb);
745
746 switch (dev_type) {
747 default:
748 if (arp->ar_pro != htons(ETH_P_IP) ||
749 htons(dev_type) != arp->ar_hrd)
750 goto out;
751 break;
752 case ARPHRD_ETHER:
753 case ARPHRD_FDDI:
754 case ARPHRD_IEEE802:
755 /*
756 * ETHERNET, and Fibre Channel (which are IEEE 802
757 * devices, according to RFC 2625) devices will accept ARP
758 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
759 * This is the case also of FDDI, where the RFC 1390 says that
760 * FDDI devices should accept ARP hardware of (1) Ethernet,
761 * however, to be more robust, we'll accept both 1 (Ethernet)
762 * or 6 (IEEE 802.2)
763 */
764 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
765 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
766 arp->ar_pro != htons(ETH_P_IP))
767 goto out;
768 break;
769 case ARPHRD_AX25:
770 if (arp->ar_pro != htons(AX25_P_IP) ||
771 arp->ar_hrd != htons(ARPHRD_AX25))
772 goto out;
773 break;
774 case ARPHRD_NETROM:
775 if (arp->ar_pro != htons(AX25_P_IP) ||
776 arp->ar_hrd != htons(ARPHRD_NETROM))
777 goto out;
778 break;
779 }
780
781 /* Understand only these message types */
782
783 if (arp->ar_op != htons(ARPOP_REPLY) &&
784 arp->ar_op != htons(ARPOP_REQUEST))
785 goto out;
786
787/*
788 * Extract fields
789 */
790 arp_ptr = (unsigned char *)(arp + 1);
791 sha = arp_ptr;
792 arp_ptr += dev->addr_len;
793 memcpy(&sip, arp_ptr, 4);
794 arp_ptr += 4;
795 switch (dev_type) {
796#if IS_ENABLED(CONFIG_FIREWIRE_NET)
797 case ARPHRD_IEEE1394:
798 break;
799#endif
800 default:
801 arp_ptr += dev->addr_len;
802 }
803 memcpy(&tip, arp_ptr, 4);
804/*
805 * Check for bad requests for 127.x.x.x and requests for multicast
806 * addresses. If this is one such, delete it.
807 */
808 if (ipv4_is_multicast(tip) ||
809 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
810 goto out;
811
812/*
813 * Special case: We must set Frame Relay source Q.922 address
814 */
815 if (dev_type == ARPHRD_DLCI)
816 sha = dev->broadcast;
817
818/*
819 * Process entry. The idea here is we want to send a reply if it is a
820 * request for us or if it is a request for someone else that we hold
821 * a proxy for. We want to add an entry to our cache if it is a reply
822 * to us or if it is a request for our address.
823 * (The assumption for this last is that if someone is requesting our
824 * address, they are probably intending to talk to us, so it saves time
825 * if we cache their address. Their address is also probably not in
826 * our cache, since ours is not in their cache.)
827 *
828 * Putting this another way, we only care about replies if they are to
829 * us, in which case we add them to the cache. For requests, we care
830 * about those for us and those for our proxies. We reply to both,
831 * and in the case of requests for us we add the requester to the arp
832 * cache.
833 */
834
835 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
836 if (sip == 0) {
837 if (arp->ar_op == htons(ARPOP_REQUEST) &&
838 inet_addr_type(net, tip) == RTN_LOCAL &&
839 !arp_ignore(in_dev, sip, tip))
840 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
841 dev->dev_addr, sha);
842 goto out;
843 }
844
845 if (arp->ar_op == htons(ARPOP_REQUEST) &&
846 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
847
848 rt = skb_rtable(skb);
849 addr_type = rt->rt_type;
850
851 if (addr_type == RTN_LOCAL) {
852 int dont_send;
853
854 dont_send = arp_ignore(in_dev, sip, tip);
855 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
856 dont_send = arp_filter(sip, tip, dev);
857 if (!dont_send) {
858 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
859 if (n) {
860 arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
861 dev, tip, sha, dev->dev_addr,
862 sha);
863 neigh_release(n);
864 }
865 }
866 goto out;
867 } else if (IN_DEV_FORWARD(in_dev)) {
868 if (addr_type == RTN_UNICAST &&
869 (arp_fwd_proxy(in_dev, dev, rt) ||
870 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
871 (rt->dst.dev != dev &&
872 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
873 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
874 if (n)
875 neigh_release(n);
876
877 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
878 skb->pkt_type == PACKET_HOST ||
879 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
880 arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
881 dev, tip, sha, dev->dev_addr,
882 sha);
883 } else {
884 pneigh_enqueue(&arp_tbl,
885 in_dev->arp_parms, skb);
886 return 0;
887 }
888 goto out;
889 }
890 }
891 }
892
893 /* Update our ARP tables */
894
895 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
896
897 if (IN_DEV_ARP_ACCEPT(in_dev)) {
898 /* Unsolicited ARP is not accepted by default.
899 It is possible, that this option should be enabled for some
900 devices (strip is candidate)
901 */
902 is_garp = arp->ar_op == htons(ARPOP_REQUEST) && tip == sip &&
903 inet_addr_type(net, sip) == RTN_UNICAST;
904
905 if (n == NULL &&
906 ((arp->ar_op == htons(ARPOP_REPLY) &&
907 inet_addr_type(net, sip) == RTN_UNICAST) || is_garp))
908 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
909 }
910
911 if (n) {
912 int state = NUD_REACHABLE;
913 int override;
914
915 /* If several different ARP replies follows back-to-back,
916 use the FIRST one. It is possible, if several proxy
917 agents are active. Taking the first reply prevents
918 arp trashing and chooses the fastest router.
919 */
920 override = time_after(jiffies,
921 n->updated +
922 NEIGH_VAR(n->parms, LOCKTIME)) ||
923 is_garp;
924
925 /* Broadcast replies and request packets
926 do not assert neighbour reachability.
927 */
928 if (arp->ar_op != htons(ARPOP_REPLY) ||
929 skb->pkt_type != PACKET_HOST)
930 state = NUD_STALE;
931 neigh_update(n, sha, state,
932 override ? NEIGH_UPDATE_F_OVERRIDE : 0);
933 neigh_release(n);
934 }
935
936out:
937 consume_skb(skb);
938 return 0;
939}
940
941static void parp_redo(struct sk_buff *skb)
942{
943 arp_process(skb);
944}
945
946
947/*
948 * Receive an arp request from the device layer.
949 */
950
951static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
952 struct packet_type *pt, struct net_device *orig_dev)
953{
954 const struct arphdr *arp;
955
956 if (dev->flags & IFF_NOARP ||
957 skb->pkt_type == PACKET_OTHERHOST ||
958 skb->pkt_type == PACKET_LOOPBACK)
959 goto freeskb;
960
961 skb = skb_share_check(skb, GFP_ATOMIC);
962 if (!skb)
963 goto out_of_mem;
964
965 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
966 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
967 goto freeskb;
968
969 arp = arp_hdr(skb);
970 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
971 goto freeskb;
972
973 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
974
975 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
976
977freeskb:
978 kfree_skb(skb);
979out_of_mem:
980 return 0;
981}
982
983/*
984 * User level interface (ioctl)
985 */
986
987/*
988 * Set (create) an ARP cache entry.
989 */
990
991static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
992{
993 if (dev == NULL) {
994 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
995 return 0;
996 }
997 if (__in_dev_get_rtnl(dev)) {
998 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
999 return 0;
1000 }
1001 return -ENXIO;
1002}
1003
1004static int arp_req_set_public(struct net *net, struct arpreq *r,
1005 struct net_device *dev)
1006{
1007 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1008 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1009
1010 if (mask && mask != htonl(0xFFFFFFFF))
1011 return -EINVAL;
1012 if (!dev && (r->arp_flags & ATF_COM)) {
1013 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
1014 r->arp_ha.sa_data);
1015 if (!dev)
1016 return -ENODEV;
1017 }
1018 if (mask) {
1019 if (pneigh_lookup(&arp_tbl, net, &ip, dev, 1) == NULL)
1020 return -ENOBUFS;
1021 return 0;
1022 }
1023
1024 return arp_req_set_proxy(net, dev, 1);
1025}
1026
1027static int arp_req_set(struct net *net, struct arpreq *r,
1028 struct net_device *dev)
1029{
1030 __be32 ip;
1031 struct neighbour *neigh;
1032 int err;
1033
1034 if (r->arp_flags & ATF_PUBL)
1035 return arp_req_set_public(net, r, dev);
1036
1037 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1038 if (r->arp_flags & ATF_PERM)
1039 r->arp_flags |= ATF_COM;
1040 if (dev == NULL) {
1041 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1042
1043 if (IS_ERR(rt))
1044 return PTR_ERR(rt);
1045 dev = rt->dst.dev;
1046 ip_rt_put(rt);
1047 if (!dev)
1048 return -EINVAL;
1049 }
1050 switch (dev->type) {
1051#if IS_ENABLED(CONFIG_FDDI)
1052 case ARPHRD_FDDI:
1053 /*
1054 * According to RFC 1390, FDDI devices should accept ARP
1055 * hardware types of 1 (Ethernet). However, to be more
1056 * robust, we'll accept hardware types of either 1 (Ethernet)
1057 * or 6 (IEEE 802.2).
1058 */
1059 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1060 r->arp_ha.sa_family != ARPHRD_ETHER &&
1061 r->arp_ha.sa_family != ARPHRD_IEEE802)
1062 return -EINVAL;
1063 break;
1064#endif
1065 default:
1066 if (r->arp_ha.sa_family != dev->type)
1067 return -EINVAL;
1068 break;
1069 }
1070
1071 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1072 err = PTR_ERR(neigh);
1073 if (!IS_ERR(neigh)) {
1074 unsigned int state = NUD_STALE;
1075 if (r->arp_flags & ATF_PERM)
1076 state = NUD_PERMANENT;
1077 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1078 r->arp_ha.sa_data : NULL, state,
1079 NEIGH_UPDATE_F_OVERRIDE |
1080 NEIGH_UPDATE_F_ADMIN);
1081 neigh_release(neigh);
1082 }
1083 return err;
1084}
1085
1086static unsigned int arp_state_to_flags(struct neighbour *neigh)
1087{
1088 if (neigh->nud_state&NUD_PERMANENT)
1089 return ATF_PERM | ATF_COM;
1090 else if (neigh->nud_state&NUD_VALID)
1091 return ATF_COM;
1092 else
1093 return 0;
1094}
1095
1096/*
1097 * Get an ARP cache entry.
1098 */
1099
1100static int arp_req_get(struct arpreq *r, struct net_device *dev)
1101{
1102 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1103 struct neighbour *neigh;
1104 int err = -ENXIO;
1105
1106 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1107 if (neigh) {
1108 read_lock_bh(&neigh->lock);
1109 memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
1110 r->arp_flags = arp_state_to_flags(neigh);
1111 read_unlock_bh(&neigh->lock);
1112 r->arp_ha.sa_family = dev->type;
1113 strlcpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1114 neigh_release(neigh);
1115 err = 0;
1116 }
1117 return err;
1118}
1119
1120static int arp_invalidate(struct net_device *dev, __be32 ip)
1121{
1122 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1123 int err = -ENXIO;
1124
1125 if (neigh) {
1126 if (neigh->nud_state & ~NUD_NOARP)
1127 err = neigh_update(neigh, NULL, NUD_FAILED,
1128 NEIGH_UPDATE_F_OVERRIDE|
1129 NEIGH_UPDATE_F_ADMIN);
1130 neigh_release(neigh);
1131 }
1132
1133 return err;
1134}
1135
1136static int arp_req_delete_public(struct net *net, struct arpreq *r,
1137 struct net_device *dev)
1138{
1139 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1140 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1141
1142 if (mask == htonl(0xFFFFFFFF))
1143 return pneigh_delete(&arp_tbl, net, &ip, dev);
1144
1145 if (mask)
1146 return -EINVAL;
1147
1148 return arp_req_set_proxy(net, dev, 0);
1149}
1150
1151static int arp_req_delete(struct net *net, struct arpreq *r,
1152 struct net_device *dev)
1153{
1154 __be32 ip;
1155
1156 if (r->arp_flags & ATF_PUBL)
1157 return arp_req_delete_public(net, r, dev);
1158
1159 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1160 if (dev == NULL) {
1161 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1162 if (IS_ERR(rt))
1163 return PTR_ERR(rt);
1164 dev = rt->dst.dev;
1165 ip_rt_put(rt);
1166 if (!dev)
1167 return -EINVAL;
1168 }
1169 return arp_invalidate(dev, ip);
1170}
1171
1172/*
1173 * Handle an ARP layer I/O control request.
1174 */
1175
1176int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1177{
1178 int err;
1179 struct arpreq r;
1180 struct net_device *dev = NULL;
1181
1182 switch (cmd) {
1183 case SIOCDARP:
1184 case SIOCSARP:
1185 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1186 return -EPERM;
1187 case SIOCGARP:
1188 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1189 if (err)
1190 return -EFAULT;
1191 break;
1192 default:
1193 return -EINVAL;
1194 }
1195
1196 if (r.arp_pa.sa_family != AF_INET)
1197 return -EPFNOSUPPORT;
1198
1199 if (!(r.arp_flags & ATF_PUBL) &&
1200 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1201 return -EINVAL;
1202 if (!(r.arp_flags & ATF_NETMASK))
1203 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1204 htonl(0xFFFFFFFFUL);
1205 rtnl_lock();
1206 if (r.arp_dev[0]) {
1207 err = -ENODEV;
1208 dev = __dev_get_by_name(net, r.arp_dev);
1209 if (dev == NULL)
1210 goto out;
1211
1212 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1213 if (!r.arp_ha.sa_family)
1214 r.arp_ha.sa_family = dev->type;
1215 err = -EINVAL;
1216 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1217 goto out;
1218 } else if (cmd == SIOCGARP) {
1219 err = -ENODEV;
1220 goto out;
1221 }
1222
1223 switch (cmd) {
1224 case SIOCDARP:
1225 err = arp_req_delete(net, &r, dev);
1226 break;
1227 case SIOCSARP:
1228 err = arp_req_set(net, &r, dev);
1229 break;
1230 case SIOCGARP:
1231 err = arp_req_get(&r, dev);
1232 break;
1233 }
1234out:
1235 rtnl_unlock();
1236 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1237 err = -EFAULT;
1238 return err;
1239}
1240
1241static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1242 void *ptr)
1243{
1244 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1245 struct netdev_notifier_change_info *change_info;
1246
1247 switch (event) {
1248 case NETDEV_CHANGEADDR:
1249 neigh_changeaddr(&arp_tbl, dev);
1250 rt_cache_flush(dev_net(dev));
1251 break;
1252 case NETDEV_CHANGE:
1253 change_info = ptr;
1254 if (change_info->flags_changed & IFF_NOARP)
1255 neigh_changeaddr(&arp_tbl, dev);
1256 break;
1257 default:
1258 break;
1259 }
1260
1261 return NOTIFY_DONE;
1262}
1263
1264static struct notifier_block arp_netdev_notifier = {
1265 .notifier_call = arp_netdev_event,
1266};
1267
1268/* Note, that it is not on notifier chain.
1269 It is necessary, that this routine was called after route cache will be
1270 flushed.
1271 */
1272void arp_ifdown(struct net_device *dev)
1273{
1274 neigh_ifdown(&arp_tbl, dev);
1275}
1276
1277
1278/*
1279 * Called once on startup.
1280 */
1281
1282static struct packet_type arp_packet_type __read_mostly = {
1283 .type = cpu_to_be16(ETH_P_ARP),
1284 .func = arp_rcv,
1285};
1286
1287static int arp_proc_init(void);
1288
1289void __init arp_init(void)
1290{
1291 neigh_table_init(&arp_tbl);
1292
1293 dev_add_pack(&arp_packet_type);
1294 arp_proc_init();
1295#ifdef CONFIG_SYSCTL
1296 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
1297#endif
1298 register_netdevice_notifier(&arp_netdev_notifier);
1299}
1300
1301#ifdef CONFIG_PROC_FS
1302#if IS_ENABLED(CONFIG_AX25)
1303
1304/* ------------------------------------------------------------------------ */
1305/*
1306 * ax25 -> ASCII conversion
1307 */
1308static char *ax2asc2(ax25_address *a, char *buf)
1309{
1310 char c, *s;
1311 int n;
1312
1313 for (n = 0, s = buf; n < 6; n++) {
1314 c = (a->ax25_call[n] >> 1) & 0x7F;
1315
1316 if (c != ' ')
1317 *s++ = c;
1318 }
1319
1320 *s++ = '-';
1321 n = (a->ax25_call[6] >> 1) & 0x0F;
1322 if (n > 9) {
1323 *s++ = '1';
1324 n -= 10;
1325 }
1326
1327 *s++ = n + '0';
1328 *s++ = '\0';
1329
1330 if (*buf == '\0' || *buf == '-')
1331 return "*";
1332
1333 return buf;
1334}
1335#endif /* CONFIG_AX25 */
1336
1337#define HBUFFERLEN 30
1338
1339static void arp_format_neigh_entry(struct seq_file *seq,
1340 struct neighbour *n)
1341{
1342 char hbuffer[HBUFFERLEN];
1343 int k, j;
1344 char tbuf[16];
1345 struct net_device *dev = n->dev;
1346 int hatype = dev->type;
1347
1348 read_lock(&n->lock);
1349 /* Convert hardware address to XX:XX:XX:XX ... form. */
1350#if IS_ENABLED(CONFIG_AX25)
1351 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1352 ax2asc2((ax25_address *)n->ha, hbuffer);
1353 else {
1354#endif
1355 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1356 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1357 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1358 hbuffer[k++] = ':';
1359 }
1360 if (k != 0)
1361 --k;
1362 hbuffer[k] = 0;
1363#if IS_ENABLED(CONFIG_AX25)
1364 }
1365#endif
1366 sprintf(tbuf, "%pI4", n->primary_key);
1367 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1368 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1369 read_unlock(&n->lock);
1370}
1371
1372static void arp_format_pneigh_entry(struct seq_file *seq,
1373 struct pneigh_entry *n)
1374{
1375 struct net_device *dev = n->dev;
1376 int hatype = dev ? dev->type : 0;
1377 char tbuf[16];
1378
1379 sprintf(tbuf, "%pI4", n->key);
1380 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1381 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1382 dev ? dev->name : "*");
1383}
1384
1385static int arp_seq_show(struct seq_file *seq, void *v)
1386{
1387 if (v == SEQ_START_TOKEN) {
1388 seq_puts(seq, "IP address HW type Flags "
1389 "HW address Mask Device\n");
1390 } else {
1391 struct neigh_seq_state *state = seq->private;
1392
1393 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1394 arp_format_pneigh_entry(seq, v);
1395 else
1396 arp_format_neigh_entry(seq, v);
1397 }
1398
1399 return 0;
1400}
1401
1402static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1403{
1404 /* Don't want to confuse "arp -a" w/ magic entries,
1405 * so we tell the generic iterator to skip NUD_NOARP.
1406 */
1407 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1408}
1409
1410/* ------------------------------------------------------------------------ */
1411
1412static const struct seq_operations arp_seq_ops = {
1413 .start = arp_seq_start,
1414 .next = neigh_seq_next,
1415 .stop = neigh_seq_stop,
1416 .show = arp_seq_show,
1417};
1418
1419static int arp_seq_open(struct inode *inode, struct file *file)
1420{
1421 return seq_open_net(inode, file, &arp_seq_ops,
1422 sizeof(struct neigh_seq_state));
1423}
1424
1425static const struct file_operations arp_seq_fops = {
1426 .owner = THIS_MODULE,
1427 .open = arp_seq_open,
1428 .read = seq_read,
1429 .llseek = seq_lseek,
1430 .release = seq_release_net,
1431};
1432
1433
1434static int __net_init arp_net_init(struct net *net)
1435{
1436 if (!proc_create("arp", S_IRUGO, net->proc_net, &arp_seq_fops))
1437 return -ENOMEM;
1438 return 0;
1439}
1440
1441static void __net_exit arp_net_exit(struct net *net)
1442{
1443 remove_proc_entry("arp", net->proc_net);
1444}
1445
1446static struct pernet_operations arp_net_ops = {
1447 .init = arp_net_init,
1448 .exit = arp_net_exit,
1449};
1450
1451static int __init arp_proc_init(void)
1452{
1453 return register_pernet_subsys(&arp_net_ops);
1454}
1455
1456#else /* CONFIG_PROC_FS */
1457
1458static int __init arp_proc_init(void)
1459{
1460 return 0;
1461}
1462
1463#endif /* CONFIG_PROC_FS */
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* linux/net/ipv4/arp.c
3 *
4 * Copyright (C) 1994 by Florian La Roche
5 *
6 * This module implements the Address Resolution Protocol ARP (RFC 826),
7 * which is used to convert IP addresses (or in the future maybe other
8 * high-level addresses) into a low-level hardware address (like an Ethernet
9 * address).
10 *
11 * Fixes:
12 * Alan Cox : Removed the Ethernet assumptions in
13 * Florian's code
14 * Alan Cox : Fixed some small errors in the ARP
15 * logic
16 * Alan Cox : Allow >4K in /proc
17 * Alan Cox : Make ARP add its own protocol entry
18 * Ross Martin : Rewrote arp_rcv() and arp_get_info()
19 * Stephen Henson : Add AX25 support to arp_get_info()
20 * Alan Cox : Drop data when a device is downed.
21 * Alan Cox : Use init_timer().
22 * Alan Cox : Double lock fixes.
23 * Martin Seine : Move the arphdr structure
24 * to if_arp.h for compatibility.
25 * with BSD based programs.
26 * Andrew Tridgell : Added ARP netmask code and
27 * re-arranged proxy handling.
28 * Alan Cox : Changed to use notifiers.
29 * Niibe Yutaka : Reply for this device or proxies only.
30 * Alan Cox : Don't proxy across hardware types!
31 * Jonathan Naylor : Added support for NET/ROM.
32 * Mike Shaver : RFC1122 checks.
33 * Jonathan Naylor : Only lookup the hardware address for
34 * the correct hardware type.
35 * Germano Caronni : Assorted subtle races.
36 * Craig Schlenter : Don't modify permanent entry
37 * during arp_rcv.
38 * Russ Nelson : Tidied up a few bits.
39 * Alexey Kuznetsov: Major changes to caching and behaviour,
40 * eg intelligent arp probing and
41 * generation
42 * of host down events.
43 * Alan Cox : Missing unlock in device events.
44 * Eckes : ARP ioctl control errors.
45 * Alexey Kuznetsov: Arp free fix.
46 * Manuel Rodriguez: Gratuitous ARP.
47 * Jonathan Layes : Added arpd support through kerneld
48 * message queue (960314)
49 * Mike Shaver : /proc/sys/net/ipv4/arp_* support
50 * Mike McLagan : Routing by source
51 * Stuart Cheshire : Metricom and grat arp fixes
52 * *** FOR 2.1 clean this up ***
53 * Lawrence V. Stefani: (08/12/96) Added FDDI support.
54 * Alan Cox : Took the AP1000 nasty FDDI hack and
55 * folded into the mainstream FDDI code.
56 * Ack spit, Linus how did you allow that
57 * one in...
58 * Jes Sorensen : Make FDDI work again in 2.1.x and
59 * clean up the APFDDI & gen. FDDI bits.
60 * Alexey Kuznetsov: new arp state machine;
61 * now it is in net/core/neighbour.c.
62 * Krzysztof Halasa: Added Frame Relay ARP support.
63 * Arnaldo C. Melo : convert /proc/net/arp to seq_file
64 * Shmulik Hen: Split arp_send to arp_create and
65 * arp_xmit so intermediate drivers like
66 * bonding can change the skb before
67 * sending (e.g. insert 8021q tag).
68 * Harald Welte : convert to make use of jenkins hash
69 * Jesper D. Brouer: Proxy ARP PVLAN RFC 3069 support.
70 */
71
72#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
73
74#include <linux/module.h>
75#include <linux/types.h>
76#include <linux/string.h>
77#include <linux/kernel.h>
78#include <linux/capability.h>
79#include <linux/socket.h>
80#include <linux/sockios.h>
81#include <linux/errno.h>
82#include <linux/in.h>
83#include <linux/mm.h>
84#include <linux/inet.h>
85#include <linux/inetdevice.h>
86#include <linux/netdevice.h>
87#include <linux/etherdevice.h>
88#include <linux/fddidevice.h>
89#include <linux/if_arp.h>
90#include <linux/skbuff.h>
91#include <linux/proc_fs.h>
92#include <linux/seq_file.h>
93#include <linux/stat.h>
94#include <linux/init.h>
95#include <linux/net.h>
96#include <linux/rcupdate.h>
97#include <linux/slab.h>
98#ifdef CONFIG_SYSCTL
99#include <linux/sysctl.h>
100#endif
101
102#include <net/net_namespace.h>
103#include <net/ip.h>
104#include <net/icmp.h>
105#include <net/route.h>
106#include <net/protocol.h>
107#include <net/tcp.h>
108#include <net/sock.h>
109#include <net/arp.h>
110#include <net/ax25.h>
111#include <net/netrom.h>
112#include <net/dst_metadata.h>
113#include <net/ip_tunnels.h>
114
115#include <linux/uaccess.h>
116
117#include <linux/netfilter_arp.h>
118
119/*
120 * Interface to generic neighbour cache.
121 */
122static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
123static bool arp_key_eq(const struct neighbour *n, const void *pkey);
124static int arp_constructor(struct neighbour *neigh);
125static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
126static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
127static void parp_redo(struct sk_buff *skb);
128static int arp_is_multicast(const void *pkey);
129
130static const struct neigh_ops arp_generic_ops = {
131 .family = AF_INET,
132 .solicit = arp_solicit,
133 .error_report = arp_error_report,
134 .output = neigh_resolve_output,
135 .connected_output = neigh_connected_output,
136};
137
138static const struct neigh_ops arp_hh_ops = {
139 .family = AF_INET,
140 .solicit = arp_solicit,
141 .error_report = arp_error_report,
142 .output = neigh_resolve_output,
143 .connected_output = neigh_resolve_output,
144};
145
146static const struct neigh_ops arp_direct_ops = {
147 .family = AF_INET,
148 .output = neigh_direct_output,
149 .connected_output = neigh_direct_output,
150};
151
152struct neigh_table arp_tbl = {
153 .family = AF_INET,
154 .key_len = 4,
155 .protocol = cpu_to_be16(ETH_P_IP),
156 .hash = arp_hash,
157 .key_eq = arp_key_eq,
158 .constructor = arp_constructor,
159 .proxy_redo = parp_redo,
160 .is_multicast = arp_is_multicast,
161 .id = "arp_cache",
162 .parms = {
163 .tbl = &arp_tbl,
164 .reachable_time = 30 * HZ,
165 .data = {
166 [NEIGH_VAR_MCAST_PROBES] = 3,
167 [NEIGH_VAR_UCAST_PROBES] = 3,
168 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
169 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
170 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
171 [NEIGH_VAR_INTERVAL_PROBE_TIME_MS] = 5 * HZ,
172 [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
173 [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
174 [NEIGH_VAR_PROXY_QLEN] = 64,
175 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
176 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
177 [NEIGH_VAR_LOCKTIME] = 1 * HZ,
178 },
179 },
180 .gc_interval = 30 * HZ,
181 .gc_thresh1 = 128,
182 .gc_thresh2 = 512,
183 .gc_thresh3 = 1024,
184};
185EXPORT_SYMBOL(arp_tbl);
186
187int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
188{
189 switch (dev->type) {
190 case ARPHRD_ETHER:
191 case ARPHRD_FDDI:
192 case ARPHRD_IEEE802:
193 ip_eth_mc_map(addr, haddr);
194 return 0;
195 case ARPHRD_INFINIBAND:
196 ip_ib_mc_map(addr, dev->broadcast, haddr);
197 return 0;
198 case ARPHRD_IPGRE:
199 ip_ipgre_mc_map(addr, dev->broadcast, haddr);
200 return 0;
201 default:
202 if (dir) {
203 memcpy(haddr, dev->broadcast, dev->addr_len);
204 return 0;
205 }
206 }
207 return -EINVAL;
208}
209
210
211static u32 arp_hash(const void *pkey,
212 const struct net_device *dev,
213 __u32 *hash_rnd)
214{
215 return arp_hashfn(pkey, dev, hash_rnd);
216}
217
218static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
219{
220 return neigh_key_eq32(neigh, pkey);
221}
222
223static int arp_constructor(struct neighbour *neigh)
224{
225 __be32 addr;
226 struct net_device *dev = neigh->dev;
227 struct in_device *in_dev;
228 struct neigh_parms *parms;
229 u32 inaddr_any = INADDR_ANY;
230
231 if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
232 memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len);
233
234 addr = *(__be32 *)neigh->primary_key;
235 rcu_read_lock();
236 in_dev = __in_dev_get_rcu(dev);
237 if (!in_dev) {
238 rcu_read_unlock();
239 return -EINVAL;
240 }
241
242 neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr);
243
244 parms = in_dev->arp_parms;
245 __neigh_parms_put(neigh->parms);
246 neigh->parms = neigh_parms_clone(parms);
247 rcu_read_unlock();
248
249 if (!dev->header_ops) {
250 neigh->nud_state = NUD_NOARP;
251 neigh->ops = &arp_direct_ops;
252 neigh->output = neigh_direct_output;
253 } else {
254 /* Good devices (checked by reading texts, but only Ethernet is
255 tested)
256
257 ARPHRD_ETHER: (ethernet, apfddi)
258 ARPHRD_FDDI: (fddi)
259 ARPHRD_IEEE802: (tr)
260 ARPHRD_METRICOM: (strip)
261 ARPHRD_ARCNET:
262 etc. etc. etc.
263
264 ARPHRD_IPDDP will also work, if author repairs it.
265 I did not it, because this driver does not work even
266 in old paradigm.
267 */
268
269 if (neigh->type == RTN_MULTICAST) {
270 neigh->nud_state = NUD_NOARP;
271 arp_mc_map(addr, neigh->ha, dev, 1);
272 } else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
273 neigh->nud_state = NUD_NOARP;
274 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
275 } else if (neigh->type == RTN_BROADCAST ||
276 (dev->flags & IFF_POINTOPOINT)) {
277 neigh->nud_state = NUD_NOARP;
278 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
279 }
280
281 if (dev->header_ops->cache)
282 neigh->ops = &arp_hh_ops;
283 else
284 neigh->ops = &arp_generic_ops;
285
286 if (neigh->nud_state & NUD_VALID)
287 neigh->output = neigh->ops->connected_output;
288 else
289 neigh->output = neigh->ops->output;
290 }
291 return 0;
292}
293
294static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
295{
296 dst_link_failure(skb);
297 kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_FAILED);
298}
299
300/* Create and send an arp packet. */
301static void arp_send_dst(int type, int ptype, __be32 dest_ip,
302 struct net_device *dev, __be32 src_ip,
303 const unsigned char *dest_hw,
304 const unsigned char *src_hw,
305 const unsigned char *target_hw,
306 struct dst_entry *dst)
307{
308 struct sk_buff *skb;
309
310 /* arp on this interface. */
311 if (dev->flags & IFF_NOARP)
312 return;
313
314 skb = arp_create(type, ptype, dest_ip, dev, src_ip,
315 dest_hw, src_hw, target_hw);
316 if (!skb)
317 return;
318
319 skb_dst_set(skb, dst_clone(dst));
320 arp_xmit(skb);
321}
322
323void arp_send(int type, int ptype, __be32 dest_ip,
324 struct net_device *dev, __be32 src_ip,
325 const unsigned char *dest_hw, const unsigned char *src_hw,
326 const unsigned char *target_hw)
327{
328 arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw,
329 target_hw, NULL);
330}
331EXPORT_SYMBOL(arp_send);
332
333static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
334{
335 __be32 saddr = 0;
336 u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
337 struct net_device *dev = neigh->dev;
338 __be32 target = *(__be32 *)neigh->primary_key;
339 int probes = atomic_read(&neigh->probes);
340 struct in_device *in_dev;
341 struct dst_entry *dst = NULL;
342
343 rcu_read_lock();
344 in_dev = __in_dev_get_rcu(dev);
345 if (!in_dev) {
346 rcu_read_unlock();
347 return;
348 }
349 switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
350 default:
351 case 0: /* By default announce any local IP */
352 if (skb && inet_addr_type_dev_table(dev_net(dev), dev,
353 ip_hdr(skb)->saddr) == RTN_LOCAL)
354 saddr = ip_hdr(skb)->saddr;
355 break;
356 case 1: /* Restrict announcements of saddr in same subnet */
357 if (!skb)
358 break;
359 saddr = ip_hdr(skb)->saddr;
360 if (inet_addr_type_dev_table(dev_net(dev), dev,
361 saddr) == RTN_LOCAL) {
362 /* saddr should be known to target */
363 if (inet_addr_onlink(in_dev, target, saddr))
364 break;
365 }
366 saddr = 0;
367 break;
368 case 2: /* Avoid secondary IPs, get a primary/preferred one */
369 break;
370 }
371 rcu_read_unlock();
372
373 if (!saddr)
374 saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
375
376 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
377 if (probes < 0) {
378 if (!(READ_ONCE(neigh->nud_state) & NUD_VALID))
379 pr_debug("trying to ucast probe in NUD_INVALID\n");
380 neigh_ha_snapshot(dst_ha, neigh, dev);
381 dst_hw = dst_ha;
382 } else {
383 probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
384 if (probes < 0) {
385 neigh_app_ns(neigh);
386 return;
387 }
388 }
389
390 if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE))
391 dst = skb_dst(skb);
392 arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
393 dst_hw, dev->dev_addr, NULL, dst);
394}
395
396static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
397{
398 struct net *net = dev_net(in_dev->dev);
399 int scope;
400
401 switch (IN_DEV_ARP_IGNORE(in_dev)) {
402 case 0: /* Reply, the tip is already validated */
403 return 0;
404 case 1: /* Reply only if tip is configured on the incoming interface */
405 sip = 0;
406 scope = RT_SCOPE_HOST;
407 break;
408 case 2: /*
409 * Reply only if tip is configured on the incoming interface
410 * and is in same subnet as sip
411 */
412 scope = RT_SCOPE_HOST;
413 break;
414 case 3: /* Do not reply for scope host addresses */
415 sip = 0;
416 scope = RT_SCOPE_LINK;
417 in_dev = NULL;
418 break;
419 case 4: /* Reserved */
420 case 5:
421 case 6:
422 case 7:
423 return 0;
424 case 8: /* Do not reply */
425 return 1;
426 default:
427 return 0;
428 }
429 return !inet_confirm_addr(net, in_dev, sip, tip, scope);
430}
431
432static int arp_accept(struct in_device *in_dev, __be32 sip)
433{
434 struct net *net = dev_net(in_dev->dev);
435 int scope = RT_SCOPE_LINK;
436
437 switch (IN_DEV_ARP_ACCEPT(in_dev)) {
438 case 0: /* Don't create new entries from garp */
439 return 0;
440 case 1: /* Create new entries from garp */
441 return 1;
442 case 2: /* Create a neighbor in the arp table only if sip
443 * is in the same subnet as an address configured
444 * on the interface that received the garp message
445 */
446 return !!inet_confirm_addr(net, in_dev, sip, 0, scope);
447 default:
448 return 0;
449 }
450}
451
452static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
453{
454 struct rtable *rt;
455 int flag = 0;
456 /*unsigned long now; */
457 struct net *net = dev_net(dev);
458
459 rt = ip_route_output(net, sip, tip, 0, l3mdev_master_ifindex_rcu(dev));
460 if (IS_ERR(rt))
461 return 1;
462 if (rt->dst.dev != dev) {
463 __NET_INC_STATS(net, LINUX_MIB_ARPFILTER);
464 flag = 1;
465 }
466 ip_rt_put(rt);
467 return flag;
468}
469
470/*
471 * Check if we can use proxy ARP for this path
472 */
473static inline int arp_fwd_proxy(struct in_device *in_dev,
474 struct net_device *dev, struct rtable *rt)
475{
476 struct in_device *out_dev;
477 int imi, omi = -1;
478
479 if (rt->dst.dev == dev)
480 return 0;
481
482 if (!IN_DEV_PROXY_ARP(in_dev))
483 return 0;
484 imi = IN_DEV_MEDIUM_ID(in_dev);
485 if (imi == 0)
486 return 1;
487 if (imi == -1)
488 return 0;
489
490 /* place to check for proxy_arp for routes */
491
492 out_dev = __in_dev_get_rcu(rt->dst.dev);
493 if (out_dev)
494 omi = IN_DEV_MEDIUM_ID(out_dev);
495
496 return omi != imi && omi != -1;
497}
498
499/*
500 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
501 *
502 * RFC3069 supports proxy arp replies back to the same interface. This
503 * is done to support (ethernet) switch features, like RFC 3069, where
504 * the individual ports are not allowed to communicate with each
505 * other, BUT they are allowed to talk to the upstream router. As
506 * described in RFC 3069, it is possible to allow these hosts to
507 * communicate through the upstream router, by proxy_arp'ing.
508 *
509 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
510 *
511 * This technology is known by different names:
512 * In RFC 3069 it is called VLAN Aggregation.
513 * Cisco and Allied Telesyn call it Private VLAN.
514 * Hewlett-Packard call it Source-Port filtering or port-isolation.
515 * Ericsson call it MAC-Forced Forwarding (RFC Draft).
516 *
517 */
518static inline int arp_fwd_pvlan(struct in_device *in_dev,
519 struct net_device *dev, struct rtable *rt,
520 __be32 sip, __be32 tip)
521{
522 /* Private VLAN is only concerned about the same ethernet segment */
523 if (rt->dst.dev != dev)
524 return 0;
525
526 /* Don't reply on self probes (often done by windowz boxes)*/
527 if (sip == tip)
528 return 0;
529
530 if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
531 return 1;
532 else
533 return 0;
534}
535
536/*
537 * Interface to link layer: send routine and receive handler.
538 */
539
540/*
541 * Create an arp packet. If dest_hw is not set, we create a broadcast
542 * message.
543 */
544struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
545 struct net_device *dev, __be32 src_ip,
546 const unsigned char *dest_hw,
547 const unsigned char *src_hw,
548 const unsigned char *target_hw)
549{
550 struct sk_buff *skb;
551 struct arphdr *arp;
552 unsigned char *arp_ptr;
553 int hlen = LL_RESERVED_SPACE(dev);
554 int tlen = dev->needed_tailroom;
555
556 /*
557 * Allocate a buffer
558 */
559
560 skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
561 if (!skb)
562 return NULL;
563
564 skb_reserve(skb, hlen);
565 skb_reset_network_header(skb);
566 arp = skb_put(skb, arp_hdr_len(dev));
567 skb->dev = dev;
568 skb->protocol = htons(ETH_P_ARP);
569 if (!src_hw)
570 src_hw = dev->dev_addr;
571 if (!dest_hw)
572 dest_hw = dev->broadcast;
573
574 /*
575 * Fill the device header for the ARP frame
576 */
577 if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
578 goto out;
579
580 /*
581 * Fill out the arp protocol part.
582 *
583 * The arp hardware type should match the device type, except for FDDI,
584 * which (according to RFC 1390) should always equal 1 (Ethernet).
585 */
586 /*
587 * Exceptions everywhere. AX.25 uses the AX.25 PID value not the
588 * DIX code for the protocol. Make these device structure fields.
589 */
590 switch (dev->type) {
591 default:
592 arp->ar_hrd = htons(dev->type);
593 arp->ar_pro = htons(ETH_P_IP);
594 break;
595
596#if IS_ENABLED(CONFIG_AX25)
597 case ARPHRD_AX25:
598 arp->ar_hrd = htons(ARPHRD_AX25);
599 arp->ar_pro = htons(AX25_P_IP);
600 break;
601
602#if IS_ENABLED(CONFIG_NETROM)
603 case ARPHRD_NETROM:
604 arp->ar_hrd = htons(ARPHRD_NETROM);
605 arp->ar_pro = htons(AX25_P_IP);
606 break;
607#endif
608#endif
609
610#if IS_ENABLED(CONFIG_FDDI)
611 case ARPHRD_FDDI:
612 arp->ar_hrd = htons(ARPHRD_ETHER);
613 arp->ar_pro = htons(ETH_P_IP);
614 break;
615#endif
616 }
617
618 arp->ar_hln = dev->addr_len;
619 arp->ar_pln = 4;
620 arp->ar_op = htons(type);
621
622 arp_ptr = (unsigned char *)(arp + 1);
623
624 memcpy(arp_ptr, src_hw, dev->addr_len);
625 arp_ptr += dev->addr_len;
626 memcpy(arp_ptr, &src_ip, 4);
627 arp_ptr += 4;
628
629 switch (dev->type) {
630#if IS_ENABLED(CONFIG_FIREWIRE_NET)
631 case ARPHRD_IEEE1394:
632 break;
633#endif
634 default:
635 if (target_hw)
636 memcpy(arp_ptr, target_hw, dev->addr_len);
637 else
638 memset(arp_ptr, 0, dev->addr_len);
639 arp_ptr += dev->addr_len;
640 }
641 memcpy(arp_ptr, &dest_ip, 4);
642
643 return skb;
644
645out:
646 kfree_skb(skb);
647 return NULL;
648}
649EXPORT_SYMBOL(arp_create);
650
651static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
652{
653 return dev_queue_xmit(skb);
654}
655
656/*
657 * Send an arp packet.
658 */
659void arp_xmit(struct sk_buff *skb)
660{
661 /* Send it off, maybe filter it using firewalling first. */
662 NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
663 dev_net(skb->dev), NULL, skb, NULL, skb->dev,
664 arp_xmit_finish);
665}
666EXPORT_SYMBOL(arp_xmit);
667
668static bool arp_is_garp(struct net *net, struct net_device *dev,
669 int *addr_type, __be16 ar_op,
670 __be32 sip, __be32 tip,
671 unsigned char *sha, unsigned char *tha)
672{
673 bool is_garp = tip == sip;
674
675 /* Gratuitous ARP _replies_ also require target hwaddr to be
676 * the same as source.
677 */
678 if (is_garp && ar_op == htons(ARPOP_REPLY))
679 is_garp =
680 /* IPv4 over IEEE 1394 doesn't provide target
681 * hardware address field in its ARP payload.
682 */
683 tha &&
684 !memcmp(tha, sha, dev->addr_len);
685
686 if (is_garp) {
687 *addr_type = inet_addr_type_dev_table(net, dev, sip);
688 if (*addr_type != RTN_UNICAST)
689 is_garp = false;
690 }
691 return is_garp;
692}
693
694/*
695 * Process an arp request.
696 */
697
698static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
699{
700 struct net_device *dev = skb->dev;
701 struct in_device *in_dev = __in_dev_get_rcu(dev);
702 struct arphdr *arp;
703 unsigned char *arp_ptr;
704 struct rtable *rt;
705 unsigned char *sha;
706 unsigned char *tha = NULL;
707 __be32 sip, tip;
708 u16 dev_type = dev->type;
709 int addr_type;
710 struct neighbour *n;
711 struct dst_entry *reply_dst = NULL;
712 bool is_garp = false;
713
714 /* arp_rcv below verifies the ARP header and verifies the device
715 * is ARP'able.
716 */
717
718 if (!in_dev)
719 goto out_free_skb;
720
721 arp = arp_hdr(skb);
722
723 switch (dev_type) {
724 default:
725 if (arp->ar_pro != htons(ETH_P_IP) ||
726 htons(dev_type) != arp->ar_hrd)
727 goto out_free_skb;
728 break;
729 case ARPHRD_ETHER:
730 case ARPHRD_FDDI:
731 case ARPHRD_IEEE802:
732 /*
733 * ETHERNET, and Fibre Channel (which are IEEE 802
734 * devices, according to RFC 2625) devices will accept ARP
735 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
736 * This is the case also of FDDI, where the RFC 1390 says that
737 * FDDI devices should accept ARP hardware of (1) Ethernet,
738 * however, to be more robust, we'll accept both 1 (Ethernet)
739 * or 6 (IEEE 802.2)
740 */
741 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
742 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
743 arp->ar_pro != htons(ETH_P_IP))
744 goto out_free_skb;
745 break;
746 case ARPHRD_AX25:
747 if (arp->ar_pro != htons(AX25_P_IP) ||
748 arp->ar_hrd != htons(ARPHRD_AX25))
749 goto out_free_skb;
750 break;
751 case ARPHRD_NETROM:
752 if (arp->ar_pro != htons(AX25_P_IP) ||
753 arp->ar_hrd != htons(ARPHRD_NETROM))
754 goto out_free_skb;
755 break;
756 }
757
758 /* Understand only these message types */
759
760 if (arp->ar_op != htons(ARPOP_REPLY) &&
761 arp->ar_op != htons(ARPOP_REQUEST))
762 goto out_free_skb;
763
764/*
765 * Extract fields
766 */
767 arp_ptr = (unsigned char *)(arp + 1);
768 sha = arp_ptr;
769 arp_ptr += dev->addr_len;
770 memcpy(&sip, arp_ptr, 4);
771 arp_ptr += 4;
772 switch (dev_type) {
773#if IS_ENABLED(CONFIG_FIREWIRE_NET)
774 case ARPHRD_IEEE1394:
775 break;
776#endif
777 default:
778 tha = arp_ptr;
779 arp_ptr += dev->addr_len;
780 }
781 memcpy(&tip, arp_ptr, 4);
782/*
783 * Check for bad requests for 127.x.x.x and requests for multicast
784 * addresses. If this is one such, delete it.
785 */
786 if (ipv4_is_multicast(tip) ||
787 (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
788 goto out_free_skb;
789
790 /*
791 * For some 802.11 wireless deployments (and possibly other networks),
792 * there will be an ARP proxy and gratuitous ARP frames are attacks
793 * and thus should not be accepted.
794 */
795 if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP))
796 goto out_free_skb;
797
798/*
799 * Special case: We must set Frame Relay source Q.922 address
800 */
801 if (dev_type == ARPHRD_DLCI)
802 sha = dev->broadcast;
803
804/*
805 * Process entry. The idea here is we want to send a reply if it is a
806 * request for us or if it is a request for someone else that we hold
807 * a proxy for. We want to add an entry to our cache if it is a reply
808 * to us or if it is a request for our address.
809 * (The assumption for this last is that if someone is requesting our
810 * address, they are probably intending to talk to us, so it saves time
811 * if we cache their address. Their address is also probably not in
812 * our cache, since ours is not in their cache.)
813 *
814 * Putting this another way, we only care about replies if they are to
815 * us, in which case we add them to the cache. For requests, we care
816 * about those for us and those for our proxies. We reply to both,
817 * and in the case of requests for us we add the requester to the arp
818 * cache.
819 */
820
821 if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
822 reply_dst = (struct dst_entry *)
823 iptunnel_metadata_reply(skb_metadata_dst(skb),
824 GFP_ATOMIC);
825
826 /* Special case: IPv4 duplicate address detection packet (RFC2131) */
827 if (sip == 0) {
828 if (arp->ar_op == htons(ARPOP_REQUEST) &&
829 inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
830 !arp_ignore(in_dev, sip, tip))
831 arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
832 sha, dev->dev_addr, sha, reply_dst);
833 goto out_consume_skb;
834 }
835
836 if (arp->ar_op == htons(ARPOP_REQUEST) &&
837 ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
838
839 rt = skb_rtable(skb);
840 addr_type = rt->rt_type;
841
842 if (addr_type == RTN_LOCAL) {
843 int dont_send;
844
845 dont_send = arp_ignore(in_dev, sip, tip);
846 if (!dont_send && IN_DEV_ARPFILTER(in_dev))
847 dont_send = arp_filter(sip, tip, dev);
848 if (!dont_send) {
849 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
850 if (n) {
851 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
852 sip, dev, tip, sha,
853 dev->dev_addr, sha,
854 reply_dst);
855 neigh_release(n);
856 }
857 }
858 goto out_consume_skb;
859 } else if (IN_DEV_FORWARD(in_dev)) {
860 if (addr_type == RTN_UNICAST &&
861 (arp_fwd_proxy(in_dev, dev, rt) ||
862 arp_fwd_pvlan(in_dev, dev, rt, sip, tip) ||
863 (rt->dst.dev != dev &&
864 pneigh_lookup(&arp_tbl, net, &tip, dev, 0)))) {
865 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
866 if (n)
867 neigh_release(n);
868
869 if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
870 skb->pkt_type == PACKET_HOST ||
871 NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
872 arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
873 sip, dev, tip, sha,
874 dev->dev_addr, sha,
875 reply_dst);
876 } else {
877 pneigh_enqueue(&arp_tbl,
878 in_dev->arp_parms, skb);
879 goto out_free_dst;
880 }
881 goto out_consume_skb;
882 }
883 }
884 }
885
886 /* Update our ARP tables */
887
888 n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
889
890 addr_type = -1;
891 if (n || arp_accept(in_dev, sip)) {
892 is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op,
893 sip, tip, sha, tha);
894 }
895
896 if (arp_accept(in_dev, sip)) {
897 /* Unsolicited ARP is not accepted by default.
898 It is possible, that this option should be enabled for some
899 devices (strip is candidate)
900 */
901 if (!n &&
902 (is_garp ||
903 (arp->ar_op == htons(ARPOP_REPLY) &&
904 (addr_type == RTN_UNICAST ||
905 (addr_type < 0 &&
906 /* postpone calculation to as late as possible */
907 inet_addr_type_dev_table(net, dev, sip) ==
908 RTN_UNICAST)))))
909 n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
910 }
911
912 if (n) {
913 int state = NUD_REACHABLE;
914 int override;
915
916 /* If several different ARP replies follows back-to-back,
917 use the FIRST one. It is possible, if several proxy
918 agents are active. Taking the first reply prevents
919 arp trashing and chooses the fastest router.
920 */
921 override = time_after(jiffies,
922 n->updated +
923 NEIGH_VAR(n->parms, LOCKTIME)) ||
924 is_garp;
925
926 /* Broadcast replies and request packets
927 do not assert neighbour reachability.
928 */
929 if (arp->ar_op != htons(ARPOP_REPLY) ||
930 skb->pkt_type != PACKET_HOST)
931 state = NUD_STALE;
932 neigh_update(n, sha, state,
933 override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0);
934 neigh_release(n);
935 }
936
937out_consume_skb:
938 consume_skb(skb);
939
940out_free_dst:
941 dst_release(reply_dst);
942 return NET_RX_SUCCESS;
943
944out_free_skb:
945 kfree_skb(skb);
946 return NET_RX_DROP;
947}
948
949static void parp_redo(struct sk_buff *skb)
950{
951 arp_process(dev_net(skb->dev), NULL, skb);
952}
953
954static int arp_is_multicast(const void *pkey)
955{
956 return ipv4_is_multicast(*((__be32 *)pkey));
957}
958
959/*
960 * Receive an arp request from the device layer.
961 */
962
963static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
964 struct packet_type *pt, struct net_device *orig_dev)
965{
966 const struct arphdr *arp;
967
968 /* do not tweak dropwatch on an ARP we will ignore */
969 if (dev->flags & IFF_NOARP ||
970 skb->pkt_type == PACKET_OTHERHOST ||
971 skb->pkt_type == PACKET_LOOPBACK)
972 goto consumeskb;
973
974 skb = skb_share_check(skb, GFP_ATOMIC);
975 if (!skb)
976 goto out_of_mem;
977
978 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
979 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
980 goto freeskb;
981
982 arp = arp_hdr(skb);
983 if (arp->ar_hln != dev->addr_len || arp->ar_pln != 4)
984 goto freeskb;
985
986 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
987
988 return NF_HOOK(NFPROTO_ARP, NF_ARP_IN,
989 dev_net(dev), NULL, skb, dev, NULL,
990 arp_process);
991
992consumeskb:
993 consume_skb(skb);
994 return NET_RX_SUCCESS;
995freeskb:
996 kfree_skb(skb);
997out_of_mem:
998 return NET_RX_DROP;
999}
1000
1001/*
1002 * User level interface (ioctl)
1003 */
1004
1005/*
1006 * Set (create) an ARP cache entry.
1007 */
1008
1009static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
1010{
1011 if (!dev) {
1012 IPV4_DEVCONF_ALL(net, PROXY_ARP) = on;
1013 return 0;
1014 }
1015 if (__in_dev_get_rtnl(dev)) {
1016 IN_DEV_CONF_SET(__in_dev_get_rtnl(dev), PROXY_ARP, on);
1017 return 0;
1018 }
1019 return -ENXIO;
1020}
1021
1022static int arp_req_set_public(struct net *net, struct arpreq *r,
1023 struct net_device *dev)
1024{
1025 __be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1026 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1027
1028 if (mask && mask != htonl(0xFFFFFFFF))
1029 return -EINVAL;
1030 if (!dev && (r->arp_flags & ATF_COM)) {
1031 dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
1032 r->arp_ha.sa_data);
1033 if (!dev)
1034 return -ENODEV;
1035 }
1036 if (mask) {
1037 if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1))
1038 return -ENOBUFS;
1039 return 0;
1040 }
1041
1042 return arp_req_set_proxy(net, dev, 1);
1043}
1044
1045static int arp_req_set(struct net *net, struct arpreq *r,
1046 struct net_device *dev)
1047{
1048 __be32 ip;
1049 struct neighbour *neigh;
1050 int err;
1051
1052 if (r->arp_flags & ATF_PUBL)
1053 return arp_req_set_public(net, r, dev);
1054
1055 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1056 if (r->arp_flags & ATF_PERM)
1057 r->arp_flags |= ATF_COM;
1058 if (!dev) {
1059 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1060
1061 if (IS_ERR(rt))
1062 return PTR_ERR(rt);
1063 dev = rt->dst.dev;
1064 ip_rt_put(rt);
1065 if (!dev)
1066 return -EINVAL;
1067 }
1068 switch (dev->type) {
1069#if IS_ENABLED(CONFIG_FDDI)
1070 case ARPHRD_FDDI:
1071 /*
1072 * According to RFC 1390, FDDI devices should accept ARP
1073 * hardware types of 1 (Ethernet). However, to be more
1074 * robust, we'll accept hardware types of either 1 (Ethernet)
1075 * or 6 (IEEE 802.2).
1076 */
1077 if (r->arp_ha.sa_family != ARPHRD_FDDI &&
1078 r->arp_ha.sa_family != ARPHRD_ETHER &&
1079 r->arp_ha.sa_family != ARPHRD_IEEE802)
1080 return -EINVAL;
1081 break;
1082#endif
1083 default:
1084 if (r->arp_ha.sa_family != dev->type)
1085 return -EINVAL;
1086 break;
1087 }
1088
1089 neigh = __neigh_lookup_errno(&arp_tbl, &ip, dev);
1090 err = PTR_ERR(neigh);
1091 if (!IS_ERR(neigh)) {
1092 unsigned int state = NUD_STALE;
1093 if (r->arp_flags & ATF_PERM)
1094 state = NUD_PERMANENT;
1095 err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
1096 r->arp_ha.sa_data : NULL, state,
1097 NEIGH_UPDATE_F_OVERRIDE |
1098 NEIGH_UPDATE_F_ADMIN, 0);
1099 neigh_release(neigh);
1100 }
1101 return err;
1102}
1103
1104static unsigned int arp_state_to_flags(struct neighbour *neigh)
1105{
1106 if (neigh->nud_state&NUD_PERMANENT)
1107 return ATF_PERM | ATF_COM;
1108 else if (neigh->nud_state&NUD_VALID)
1109 return ATF_COM;
1110 else
1111 return 0;
1112}
1113
1114/*
1115 * Get an ARP cache entry.
1116 */
1117
1118static int arp_req_get(struct arpreq *r, struct net_device *dev)
1119{
1120 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1121 struct neighbour *neigh;
1122 int err = -ENXIO;
1123
1124 neigh = neigh_lookup(&arp_tbl, &ip, dev);
1125 if (neigh) {
1126 if (!(READ_ONCE(neigh->nud_state) & NUD_NOARP)) {
1127 read_lock_bh(&neigh->lock);
1128 memcpy(r->arp_ha.sa_data, neigh->ha,
1129 min(dev->addr_len, sizeof(r->arp_ha.sa_data_min)));
1130 r->arp_flags = arp_state_to_flags(neigh);
1131 read_unlock_bh(&neigh->lock);
1132 r->arp_ha.sa_family = dev->type;
1133 strscpy(r->arp_dev, dev->name, sizeof(r->arp_dev));
1134 err = 0;
1135 }
1136 neigh_release(neigh);
1137 }
1138 return err;
1139}
1140
1141int arp_invalidate(struct net_device *dev, __be32 ip, bool force)
1142{
1143 struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
1144 int err = -ENXIO;
1145 struct neigh_table *tbl = &arp_tbl;
1146
1147 if (neigh) {
1148 if ((READ_ONCE(neigh->nud_state) & NUD_VALID) && !force) {
1149 neigh_release(neigh);
1150 return 0;
1151 }
1152
1153 if (READ_ONCE(neigh->nud_state) & ~NUD_NOARP)
1154 err = neigh_update(neigh, NULL, NUD_FAILED,
1155 NEIGH_UPDATE_F_OVERRIDE|
1156 NEIGH_UPDATE_F_ADMIN, 0);
1157 write_lock_bh(&tbl->lock);
1158 neigh_release(neigh);
1159 neigh_remove_one(neigh, tbl);
1160 write_unlock_bh(&tbl->lock);
1161 }
1162
1163 return err;
1164}
1165
1166static int arp_req_delete_public(struct net *net, struct arpreq *r,
1167 struct net_device *dev)
1168{
1169 __be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
1170 __be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
1171
1172 if (mask == htonl(0xFFFFFFFF))
1173 return pneigh_delete(&arp_tbl, net, &ip, dev);
1174
1175 if (mask)
1176 return -EINVAL;
1177
1178 return arp_req_set_proxy(net, dev, 0);
1179}
1180
1181static int arp_req_delete(struct net *net, struct arpreq *r,
1182 struct net_device *dev)
1183{
1184 __be32 ip;
1185
1186 if (r->arp_flags & ATF_PUBL)
1187 return arp_req_delete_public(net, r, dev);
1188
1189 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
1190 if (!dev) {
1191 struct rtable *rt = ip_route_output(net, ip, 0, RTO_ONLINK, 0);
1192 if (IS_ERR(rt))
1193 return PTR_ERR(rt);
1194 dev = rt->dst.dev;
1195 ip_rt_put(rt);
1196 if (!dev)
1197 return -EINVAL;
1198 }
1199 return arp_invalidate(dev, ip, true);
1200}
1201
1202/*
1203 * Handle an ARP layer I/O control request.
1204 */
1205
1206int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
1207{
1208 int err;
1209 struct arpreq r;
1210 struct net_device *dev = NULL;
1211
1212 switch (cmd) {
1213 case SIOCDARP:
1214 case SIOCSARP:
1215 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1216 return -EPERM;
1217 fallthrough;
1218 case SIOCGARP:
1219 err = copy_from_user(&r, arg, sizeof(struct arpreq));
1220 if (err)
1221 return -EFAULT;
1222 break;
1223 default:
1224 return -EINVAL;
1225 }
1226
1227 if (r.arp_pa.sa_family != AF_INET)
1228 return -EPFNOSUPPORT;
1229
1230 if (!(r.arp_flags & ATF_PUBL) &&
1231 (r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
1232 return -EINVAL;
1233 if (!(r.arp_flags & ATF_NETMASK))
1234 ((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
1235 htonl(0xFFFFFFFFUL);
1236 rtnl_lock();
1237 if (r.arp_dev[0]) {
1238 err = -ENODEV;
1239 dev = __dev_get_by_name(net, r.arp_dev);
1240 if (!dev)
1241 goto out;
1242
1243 /* Mmmm... It is wrong... ARPHRD_NETROM==0 */
1244 if (!r.arp_ha.sa_family)
1245 r.arp_ha.sa_family = dev->type;
1246 err = -EINVAL;
1247 if ((r.arp_flags & ATF_COM) && r.arp_ha.sa_family != dev->type)
1248 goto out;
1249 } else if (cmd == SIOCGARP) {
1250 err = -ENODEV;
1251 goto out;
1252 }
1253
1254 switch (cmd) {
1255 case SIOCDARP:
1256 err = arp_req_delete(net, &r, dev);
1257 break;
1258 case SIOCSARP:
1259 err = arp_req_set(net, &r, dev);
1260 break;
1261 case SIOCGARP:
1262 err = arp_req_get(&r, dev);
1263 break;
1264 }
1265out:
1266 rtnl_unlock();
1267 if (cmd == SIOCGARP && !err && copy_to_user(arg, &r, sizeof(r)))
1268 err = -EFAULT;
1269 return err;
1270}
1271
1272static int arp_netdev_event(struct notifier_block *this, unsigned long event,
1273 void *ptr)
1274{
1275 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1276 struct netdev_notifier_change_info *change_info;
1277 struct in_device *in_dev;
1278 bool evict_nocarrier;
1279
1280 switch (event) {
1281 case NETDEV_CHANGEADDR:
1282 neigh_changeaddr(&arp_tbl, dev);
1283 rt_cache_flush(dev_net(dev));
1284 break;
1285 case NETDEV_CHANGE:
1286 change_info = ptr;
1287 if (change_info->flags_changed & IFF_NOARP)
1288 neigh_changeaddr(&arp_tbl, dev);
1289
1290 in_dev = __in_dev_get_rtnl(dev);
1291 if (!in_dev)
1292 evict_nocarrier = true;
1293 else
1294 evict_nocarrier = IN_DEV_ARP_EVICT_NOCARRIER(in_dev);
1295
1296 if (evict_nocarrier && !netif_carrier_ok(dev))
1297 neigh_carrier_down(&arp_tbl, dev);
1298 break;
1299 default:
1300 break;
1301 }
1302
1303 return NOTIFY_DONE;
1304}
1305
1306static struct notifier_block arp_netdev_notifier = {
1307 .notifier_call = arp_netdev_event,
1308};
1309
1310/* Note, that it is not on notifier chain.
1311 It is necessary, that this routine was called after route cache will be
1312 flushed.
1313 */
1314void arp_ifdown(struct net_device *dev)
1315{
1316 neigh_ifdown(&arp_tbl, dev);
1317}
1318
1319
1320/*
1321 * Called once on startup.
1322 */
1323
1324static struct packet_type arp_packet_type __read_mostly = {
1325 .type = cpu_to_be16(ETH_P_ARP),
1326 .func = arp_rcv,
1327};
1328
1329#ifdef CONFIG_PROC_FS
1330#if IS_ENABLED(CONFIG_AX25)
1331
1332/*
1333 * ax25 -> ASCII conversion
1334 */
1335static void ax2asc2(ax25_address *a, char *buf)
1336{
1337 char c, *s;
1338 int n;
1339
1340 for (n = 0, s = buf; n < 6; n++) {
1341 c = (a->ax25_call[n] >> 1) & 0x7F;
1342
1343 if (c != ' ')
1344 *s++ = c;
1345 }
1346
1347 *s++ = '-';
1348 n = (a->ax25_call[6] >> 1) & 0x0F;
1349 if (n > 9) {
1350 *s++ = '1';
1351 n -= 10;
1352 }
1353
1354 *s++ = n + '0';
1355 *s++ = '\0';
1356
1357 if (*buf == '\0' || *buf == '-') {
1358 buf[0] = '*';
1359 buf[1] = '\0';
1360 }
1361}
1362#endif /* CONFIG_AX25 */
1363
1364#define HBUFFERLEN 30
1365
1366static void arp_format_neigh_entry(struct seq_file *seq,
1367 struct neighbour *n)
1368{
1369 char hbuffer[HBUFFERLEN];
1370 int k, j;
1371 char tbuf[16];
1372 struct net_device *dev = n->dev;
1373 int hatype = dev->type;
1374
1375 read_lock(&n->lock);
1376 /* Convert hardware address to XX:XX:XX:XX ... form. */
1377#if IS_ENABLED(CONFIG_AX25)
1378 if (hatype == ARPHRD_AX25 || hatype == ARPHRD_NETROM)
1379 ax2asc2((ax25_address *)n->ha, hbuffer);
1380 else {
1381#endif
1382 for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
1383 hbuffer[k++] = hex_asc_hi(n->ha[j]);
1384 hbuffer[k++] = hex_asc_lo(n->ha[j]);
1385 hbuffer[k++] = ':';
1386 }
1387 if (k != 0)
1388 --k;
1389 hbuffer[k] = 0;
1390#if IS_ENABLED(CONFIG_AX25)
1391 }
1392#endif
1393 sprintf(tbuf, "%pI4", n->primary_key);
1394 seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s * %s\n",
1395 tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
1396 read_unlock(&n->lock);
1397}
1398
1399static void arp_format_pneigh_entry(struct seq_file *seq,
1400 struct pneigh_entry *n)
1401{
1402 struct net_device *dev = n->dev;
1403 int hatype = dev ? dev->type : 0;
1404 char tbuf[16];
1405
1406 sprintf(tbuf, "%pI4", n->key);
1407 seq_printf(seq, "%-16s 0x%-10x0x%-10x%s * %s\n",
1408 tbuf, hatype, ATF_PUBL | ATF_PERM, "00:00:00:00:00:00",
1409 dev ? dev->name : "*");
1410}
1411
1412static int arp_seq_show(struct seq_file *seq, void *v)
1413{
1414 if (v == SEQ_START_TOKEN) {
1415 seq_puts(seq, "IP address HW type Flags "
1416 "HW address Mask Device\n");
1417 } else {
1418 struct neigh_seq_state *state = seq->private;
1419
1420 if (state->flags & NEIGH_SEQ_IS_PNEIGH)
1421 arp_format_pneigh_entry(seq, v);
1422 else
1423 arp_format_neigh_entry(seq, v);
1424 }
1425
1426 return 0;
1427}
1428
1429static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
1430{
1431 /* Don't want to confuse "arp -a" w/ magic entries,
1432 * so we tell the generic iterator to skip NUD_NOARP.
1433 */
1434 return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_SKIP_NOARP);
1435}
1436
1437static const struct seq_operations arp_seq_ops = {
1438 .start = arp_seq_start,
1439 .next = neigh_seq_next,
1440 .stop = neigh_seq_stop,
1441 .show = arp_seq_show,
1442};
1443#endif /* CONFIG_PROC_FS */
1444
1445static int __net_init arp_net_init(struct net *net)
1446{
1447 if (!proc_create_net("arp", 0444, net->proc_net, &arp_seq_ops,
1448 sizeof(struct neigh_seq_state)))
1449 return -ENOMEM;
1450 return 0;
1451}
1452
1453static void __net_exit arp_net_exit(struct net *net)
1454{
1455 remove_proc_entry("arp", net->proc_net);
1456}
1457
1458static struct pernet_operations arp_net_ops = {
1459 .init = arp_net_init,
1460 .exit = arp_net_exit,
1461};
1462
1463void __init arp_init(void)
1464{
1465 neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
1466
1467 dev_add_pack(&arp_packet_type);
1468 register_pernet_subsys(&arp_net_ops);
1469#ifdef CONFIG_SYSCTL
1470 neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
1471#endif
1472 register_netdevice_notifier(&arp_netdev_notifier);
1473}